Stability of microgrid cluster with Diverse Energy Sources: A multi-objective solution using NSGA-II based controller

The stability of microgrids with increased penetration of renewables is a major concern. This is mainly due to their intermittent nature varying from time to time. While designing the stabilisers, the amplitude of the control signals is not given due consideration. This work develops frequency controller systems for a microgrid cluster composed of several energy sources. In addition to the frequency deviation in microgrids, the aspect of controller output signals has also been considered. A dynamic model of four microgrids linked with tie-lines is developed. The frequency stability is ensured utilising a fractional order controller using the Non-dominated Sorting Genetic Algorithm - II (NSGA-II). The multi-objective problem is formulated with opposing objectives as frequency deviation and the controller output signal for determining the controller. The performance is compared with Tilt Integral Derivative (TID), TID with filter (TIDF), Proportional Integral Derivative (PID) and PID with filter (PIDF) controllers. Besides, the superiority of the algorithm is analysed by comparing the results with those from other algorithms in the literature. The effectiveness is analysed under numerous scenarios of load and renewable uncertainties. Further, the sensitivity investigation has also been performed by varying the internal parameters within the range of +/- 40%.

Automated summary

This study focuses on improving the stability of microgrids by developing frequency controller systems, comparing performance with various algorithms, and analyzing sensitivity under different scenarios of load and renewable uncertainties, ultimately determining more effective controllers.